Upgrade Docker image to Alpine Linux 3.7
Upgrade Docker image to Alpine Linux 3.7

stinnux/kanboard,BlueTeck/kanboard,filhocf/kanboard,thylo/kanboard,BlueTeck/kanboard,filhocf/kanboard,BlueTeck/kanboard,kanboard/kanboard,fguillot/kanboard,stinnux/kanboard,fguillot/kanboard,renothing/kanboard,oliviermaridat/kanboard,libin/kanboard,fguillot/kanboard,stinnux/kanboard,renothing/kanboard,kanboard/kanboard,filhocf/kanboard,renothing/kanboard,oliviermaridat/kanboard,thylo/kanboard,oliviermaridat/kanboard,thylo/kanboard,libin/kanboard,kanboard/kanboard